The correct answer is: A. the, the, the
The reason is that the train was supposed to depart from Platform 8, so the speaker and their companions were waiting on the wrong platform. The word “the” is used before a specific noun, and in this case, the platform is specific because it is the one that the train was supposed to depart from.
The other options are incorrect because they do not use the definite article “the” before the noun “platform.” In option B, the word “no article” is used before the noun “platform.” This is incorrect because the platform is specific, so the definite article “the” should be used. In option C, the word “no article” is used twice, before both nouns “platform.” This is incorrect because the first platform is specific, so the definite article “the” should be used, but the second platform is not specific, so the indefinite article “a” should be used. In option D, the word “the” is used before the first noun “platform,” but the word “a” is used before the second noun “platform.” This is incorrect because both platforms are specific, so the definite article “the” should be used before both nouns.